In Japan the predecessor to digital broadcast services was CS digital broadcasting that uses a communication satellite, which was then followed with the commencement of BS digital broadcasting that uses a broadcast satellite. Currently, a new communication satellite that is located at longitude 110 degrees east, the same as BS (broadcast satellite), has been launched, and 110 degree CS digital broadcasting using this communication satellite is taking place.
Similarly with terrestrial broadcasting, the transition is being made from the present analog broadcasting to digital broadcasting. Analog broadcasting is set to end in 2011, when all terrestrial broadcasting will become digital.
In digital broadcasting, since it is possible to compress the amount of information of video and send the video in a compressed state, multi-channel broadcasting that sends a significantly larger amount of programs compared to analog broadcasting is being carried out.
With the increasing prevalence of digital broadcast services, the number of broadcast channels is growing (currently exceeding 300 channels, and increasing). While with such channels it is hoped that programs that conform closely with a user's preferences can be provided to the user, the user is forced to spend considerable time and effort to examine large amounts of program information in order to find channels providing programs that meet his/her preferences from among such a large number of channels. It is also possible that the user will miss out subscribing to a particular pay channel meeting his/her preferences because he/she was unable to find the channel.
In view of such issues, conventional techniques for introducing a user of a multi-channel program distribution service to appropriate channels to which he/she does not yet subscribe have been proposed (for instance, see patent document 1).
This technique calculates viewer ratings data relating to all channels of all users subscribing to the service, and performs cluster analysis of the calculated viewer ratings data to determine viewing patterns showing the viewing tendencies of all the subscribing users. The determined viewing patterns are matched with the viewing pattern of a target user, one viewing pattern is selected, and from among channels included in the selected viewing pattern, channels that the user does not yet subscribe to, and that are expected to conform to the user's preferences, are suggested to the user.
Patent Document 1: Japanese Patent Application Publication No. 2001-157191